Abstract:

An electronic unit for measuring operating parameters of a vehicle wheel,
including an electronic module (1) and an inflation valve (2) comprising
a body (6, 7) designed to extend through an orifice arranged in a wheel
rim, and an assembly head (4) separated from the body by a shoulder
forming a face for locking the inflation valve against the rim. The
electronic module (1) includes an outer wall (13, 14) defining a lateral
housing for the assembly head (4) of the inflation valve (2), delimited
by a metal plate (11) made in one piece with the electronic module, for
pressing of the locking face of the assembly head, and furnished with a
notch for the body (6, 7) of the inflation valve to pass through.

Claims:

1. An electronic unit for measuring operating parameters of a vehicle
wheel, comprising an electronic module (1) and an inflation valve (2) for
fixedly attaching said electronic module to a wheel rim (23), comprising
a body (3) designed to extend through an orifice made in the rim (23) and
an assembly head (4) separated from the body (3) by a shoulder (8)
forming a face for locking said inflation valve against said rim, said
electronic unit being characterized in that the electronic module (1)
comprises an outer wall (13, 14) defining a lateral housing (12) for the
assembly head (4) of the inflation valve (2), delimited by a metal plate
(11) made in one piece with said electronic module, for pressing of the
locking face (8) of said assembly head, and furnished with a notch (20)
for the body (3) of said inflation valve to pass through.

2. The electronic unit as claimed in claim 1, characterized in that the
notch (20) of the metal plate (11) has a shape forming retention means
for the body (3) of the inflation valve (2) extending through said notch.

3. The electronic unit as claimed in claim 1 whose electronic module (1)
is made by molding of a plastic, characterized in that the metal plate
(11) consists of an insert that is overmolded when said electronic module
is produced.

4. The electronic unit as claimed in claim 3, characterized in that the
metal plate (11) is pierced with two openings (22) positioned
respectively on either side of the notch (20) and suitable for being
filled when the electronic module (1) is molded.

5. The electronic unit as claimed in claim 1, characterized in that the
metal plate (11) and the locking face (8) of the assembly head (4) have
cylindrical contact faces (21) allowing the inclination of the electronic
module (1) to be adjusted relative to the longitudinal axis of the
inflation valve (2), before the latter is locked against the rim (23).

6. The electronic unit as claimed in claim 5, characterized in that the
notch (20) of the metal plate (11) has a section (20a, 20b) of increasing
thickness from the bottom of said notch to each of the ends of the
latter.

7. The electronic unit as claimed in claim 1, characterized in that the
electronic module (1) comprises a transverse wall (13) bordered by a
peripheral return (14), on which two parallel external ribs (15, 16) are
arranged extending into two consoles (17) between the ends of which the
metal plate (11) extends, so that the lateral housing (12) is delimited
by said metal plate, said consoles and the peripheral return (14).

8. The electronic unit as claimed in claim 7 whose inflation valve (2) is
pierced with an axial air flow duct (5) emerging at a face (9), called
the rear face, of the assembly head (4) opposite to the locking face (8),
characterized in that the lateral housing (12) comprises two internal
ribs (19) protruding into said lateral housing, arranged so as to define
two linear pressure surfaces for the rear face (9) of the assembly head
(4), and placed so as to extend on either side of the outflow (5a) of the
air duct (5).

9. The electronic unit as claimed in claim 2 whose electronic module (1)
is made by molding of a plastic, characterized in that the metal plate
(11) consists of an insert that is overmolded when said electronic module
is produced.

10. The electronic unit as claimed in claim 9, characterized in that the
metal plate (11) is pierced with two openings (22) positioned
respectively on either side of the notch (20) and suitable for being
filled when the electronic module (1) is molded.

11. The electronic unit as claimed in claim 2, characterized in that the
metal plate (11) and the locking face (8) of the assembly head (4) have
cylindrical contact faces (21) allowing the inclination of the electronic
module (1) to be adjusted relative to the longitudinal axis of the
inflation valve (2), before the latter is locked against the rim (23).

12. The electronic unit as claimed in claim 3, characterized in that the
metal plate (11) and the locking face (8) of the assembly head (4) have
cylindrical contact faces (21) allowing the inclination of the electronic
module (1) to be adjusted relative to the longitudinal axis of the
inflation valve (2), before the latter is locked against the rim (23).

13. The electronic unit as claimed in claim 4, characterized in that the
metal plate (11) and the locking face (8) of the assembly head (4) have
cylindrical contact faces (21) allowing the inclination of the electronic
module (1) to be adjusted relative to the longitudinal axis of the
inflation valve (2), before the latter is locked against the rim (23).

14. The electronic unit as claimed in claim 2, characterized in that the
electronic module (1) comprises a transverse wall (13) bordered by a
peripheral return (14), on which two parallel external ribs (15, 16) are
arranged extending into two consoles (17) between the ends of which the
metal plate (11) extends, so that the lateral housing (12) is delimited
by said metal plate, said consoles and the peripheral return (14).

15. The electronic unit as claimed in claim 3, characterized in that the
electronic module (1) comprises a transverse wall (13) bordered by a
peripheral return (14), on which two parallel external ribs (15, 16) are
arranged extending into two consoles (17) between the ends of which the
metal plate (11) extends, so that the lateral housing (12) is delimited
by said metal plate, said consoles and the peripheral return (14).

16. The electronic unit as claimed in claim 4, characterized in that the
electronic module (1) comprises a transverse wall (13) bordered by a
peripheral return (14), on which two parallel external ribs (15, 16) are
arranged extending into two consoles (17) between the ends of which the
metal plate (11) extends, so that the lateral housing (12) is delimited
by said metal plate, said consoles and the peripheral return (14).

17. The electronic unit as claimed in claim 5, characterized in that the
electronic module (1) comprises a transverse wall (13) bordered by a
peripheral return (14), on which two parallel external ribs (15, 16) are
arranged extending into two consoles (17) between the ends of which the
metal plate (11) extends, so that the lateral housing (12) is delimited
by said metal plate, said consoles and the peripheral return (14).

18. The electronic unit as claimed in claim 6, characterized in that the
electronic module (1) comprises a transverse wall (13) bordered by a
peripheral return (14), on which two parallel external ribs (15, 16) are
arranged extending into two consoles (17) between the ends of which the
metal plate (11) extends, so that the lateral housing (12) is delimited
by said metal plate, said consoles and the peripheral return (14).

Description:

[0001]The invention relates to an electronic unit for measuring operating
parameters of a vehicle wheel, comprising an electronic module and an
inflation valve for fixedly attaching said electronic module to a wheel
rim.

[0002]More and more motor vehicles have systems for monitoring and/or
measuring parameters comprising sensors mounted on said vehicle.

[0003]As an example relating to such systems, mention may be made of the
monitoring systems comprising electronic modules mounted on each of the
vehicle wheels, dedicated to measuring parameters such as pressure and/or
temperature of the tires fitted to these wheels, and designed to inform
the driver of any abnormal variation of the measured parameter.

[0004]One of the current solutions most commonly used in order to attach
the electronic modules to the wheel rims consists in producing electronic
units each consisting of an electronic module and an inflation valve
assembled with said electronic module for fixedly attaching the latter to
a wheel rim.

[0005]In addition, each electronic module then conventionally comprises an
external "eyelet" and each inflation valve comprises a body designed to
extend through the eyelet and an orifice made in the rim, and an assembly
head separated from the body by a shoulder forming a face for locking the
eyelet and said inflation valve against said rim.

[0006]Such a design makes it possible to obtain a screwing torque capable
of ensuring a correct retention of the electronic modules despite the
considerable stresses (centrifugal force, vibrations, accelerations,
etc.) to which the latter are subjected.

[0007]However, the transmission of the forces makes it necessary to
significantly stiffen the electronic modules and therefore leads to
making the latter complex.

[0008]In addition, the principle of assembling the inflation valve on the
electronic module requires arranging a dead volume specifically dedicated
to the installation of the inflation valve, and leads to considerable
overdimensioning and excess weight of the electronic modules.

[0009]The present invention aims to alleviate these disadvantages and its
main objective is to provide an electronic unit capable of withstanding
the considerable stresses and provided with an electronic module having
optimally reduced size and weight.

[0010]Accordingly, the subject of the invention is an electronic unit
comprising an electronic module and an inflation valve for fixedly
attaching said electronic module to a wheel rim, comprising a body
designed to extend through an orifice made in the rim and an assembly
head separated from the body by a shoulder forming a face for locking
said inflation valve against said rim.

[0011]According to the invention, the electronic module of this electronic
unit comprises an outer wall defining a lateral housing for the assembly
head of the inflation valve, delimited by a metal plate made in one piece
with said electronic module, for pressing of the locking face of said
assembly head, and furnished with a notch for the body of said inflation
valve to pass through.

[0012]According to the invention, the assembly head comes to be wedged and
locked against a metal plate which makes it possible to produce a
kinematic chain for transmitting forces consisting only of contacts
between metal parts and therefore capable of ensuring an increased
retention of the screwing torque.

[0013]In addition, the installation of the inflation valve does not
require a dead zone because the assembly head may be inserted directly
into the lateral housing designed to receive it. Accordingly, the
dimensions and the weight of the electronic modules may be optimized.

[0014]According to an advantageous embodiment of the invention, the notch
of the metal plate has a shape forming a retention means for the body of
the inflation valve extending through said notch.

[0015]This arrangement makes it possible to obtain a preassembly of the
two elements of each electronic unit in particular making the storage and
handling of the latter easier until it is attached to the rim.

[0016]It should also be noted that, because the shape of the notch forms a
means for retaining the inflation valve, the body of the inflation valve
must be presented inclined "slantwise" in order to slide inside this
notch in order to be held therein. However, this installation operation
does not require any specific dead volume, so that the dimensions of the
electronic modules are not affected by such an installation.

[0017]Furthermore, in an advantageous manner according to the invention,
the electronic module is made by molding of a plastic, and the metal
plate consists of an insert that is overmolded when said electronic
module is produced.

[0018]In addition, the metal plate is then also advantageously pierced
with two openings positioned respectively on either side of the notch and
suitable for being filled when the electronic module is molded.

[0019]Furthermore, the metal plate and the locking face of the assembly
head advantageously have cylindrical contact faces allowing the
inclination of the electronic module to be adjusted relative to the
longitudinal axis of the inflation valve, before the latter is locked
against the rim. Such an articulation makes it possible to adjust the
position of the electronic modules according to the profiles of the rims,
particularly for the purpose of keeping said electronic modules in
contact with the bottom of the rim and thereby limiting the stresses
sustained.

[0020]According to another advantageous embodiment of the invention, the
notch of the metal plate has a section of increasing thickness from the
bottom of said notch to each of the ends of the latter. This variable
thickness makes it possible specifically to produce a cam profile which
tends to oppose the tilting of the electronic module under the effect of
centrifugal force.

[0021]Furthermore, in order to stiffen the electronic module, the latter
advantageously comprises a transverse wall bordered by a peripheral
return, on which two parallel external ribs are arranged extending into
two consoles between the ends of which the metal plate extends, so that
the lateral housing is delimited by said metal plate, said consoles and
the peripheral return.

[0022]In addition, in order to make it easier for the air to travel
through the axial air flow duct usually pierced in the inflation valve
and emerging at a face, called the rear face, of the assembly head
opposite to the locking face, the lateral housing advantageously
comprises two internal ribs protruding into said lateral housing,
arranged so as to define two linear pressure surfaces for the rear face
of the assembly head, and placed so as to extend on either side of the
outflow of the air duct.

[0023]It will be noted that the invention makes it possible to fixedly
attach (and detach) quickly and very easily the module and the inflation
valve. Specifically, these two elements are simply nested in one another
and held in place before final fastening by simple retention means. The
fastening and the final (but reversible) locking of the assembly
(module+valve) is carried out only when the valve is fastened to the rim
by means of a conventional nut. Placing the module on the valve is
therefore easy and not very costly.

[0024]Other features, objects and advantages of the invention will emerge
from the following detailed description with reference to the appended
drawings which, as a nonlimiting example, represent a preferred
embodiment thereof. In these drawings:

[0025]FIG. 1 is a view in perspective of an electronic unit according to
the invention,

[0026]FIG. 2 is a view in perspective in exploded mode of this electronic
unit,

[0028]The electronic unit according to the invention shown as an example
in the figures is designed to be installed on a vehicle wheel for the
purpose of measuring operating parameters (pressure, temperature,
acceleration, etc.) of said wheel and of transmitting the measured data
to a central unit installed on the vehicle.

[0029]This electronic unit consists of an electronic module 1 suitable for
being installed inside the casing of a tire, and an inflation valve 2
articulated on said electronic module, for fixedly attaching the latter
to the rim of the wheel fitted with this tire.

[0030]First, the inflation valve 2 is made in a single piece and comprises
a cylindrical body 3 (FIG. 2) extended by an assembly head 4, said body
and assembly head being pierced with an axial air flow duct 5 emerging at
the rear face 9 of the assembly head 4.

[0031]The body 3 of this inflation valve 4 also consists of two
cylindrical longitudinal sections of different diameters: [0032]an end
section 6 of lesser diameter, furnished with an end portion that is
threaded for the installation of a cap 26 (FIG. 3) for closing off said
air flow duct 5 (FIG. 1), [0033]and an intermediate section 7 extended by
the assembly head 4, also having an end portion 7a that is threaded for
the attachment of the electronic unit to the rim.

[0034]The assembly head 4 of this inflation valve 2 has, for its part, a
width greater than that of the diameter of the intermediate section 7 and
a height substantially equal to said diameter, so as to be separated from
the body 3 by a shoulder 8 forming a transverse face, called the locking
face, being divided into two half-faces 8a, 8b distributed symmetrically
on either side of said body.

[0035]In addition, each of these two half-faces 8a, 8b has a convex
rounded shape suitable for allowing the inflation valve 2 to pivot about
an axis perpendicular to the axis of symmetry V of the latter.

[0036]The rear face 9 of this assembly head 4 consists, for its part, of a
flat face lying on an axis inclined at approximately 130° relative
to the longitudinal axis of the inflation valve 2.

[0037]The electronic module 1 of this electronic unit consists, for its
part, of an actual module 10 and a metal insert 11, suitable for
delimiting a housing 12 for the assembly head 4 of the inflation valve 2.
In addition, the module 10 is made by molding of a plastic and the insert
11 is overmolded when said electronic module is produced.

[0038]First, the module 10 consists in a hollow casing designed to house
"the electronics" of the electronic unit and formed by a transverse wall
13 bordered by a peripheral return 14.

[0039]In addition, two parallel external ribs 15, 16 are arranged on the
transverse wall 13, said ribs extending into two consoles 17 conformed,
during the molding, in order to each delimit a groove 18 inserting by
overmolding one of the ends of the insert 11.

[0040]As shown in the figures, the two consoles 17, the insert 11 and the
return 14 are arranged so as to delimit a lateral housing 12 of a shape
suitable for housing the assembly head 4.

[0041]It should be noted that, for this purpose, the length 14b (FIG. 3)
of the return 14 corresponding to the housing 12 forms an inclined face
paired with the rear face 9 of the assembly head 4, while the portion of
length 14a (FIG. 2) of the return 14 outside this housing 12 is
orthogonal to the transverse face 13.

[0042]Finally, the lateral housing 12 comprises two internal ribs 19
arranged in protrusion relative to the return 14b, inside said lateral
housing, so as to define two linear pressure surfaces for the rear face 9
of the assembly head 4, and placed so as to extend on either side of the
outflow 5a (FIG. 3) of the air duct 5.

[0043]Finally, the insert 11 (FIG. 2) consists of a metal plate for
pressing of the locking face 8 of the assembly head 4 of the inflation
valve 2, furnished with a notch 20 for the body 3 of said inflation valve
to pass through.

[0044]In addition, the shape of this notch 20 forms a means for retaining
the intermediate section 7 of the body 3 of the inflation valve 2
extending through said notch.

[0045]Finally, this notch 20 has a section 20a of increasing thickness
from the bottom of said notch to each of the ends 20b of the latter.

[0046]On either side of this notch 20, the insert 11 comprises a concave
rounded bearing surface 21 for receiving and for pressing the locking
face 8 of the assembly head 4.

[0047]Finally, the insert 1 comprises two openings 22 positioned
respectively on either side of the notch 20 and suitable for extending
inside the "grooves" 18 in order to be filled when the electronic module
1 is molded.

[0048]The electronic module 1 and the inflation valve 2 of the electronic
unit according to the invention may, first, be preassembled, thanks to
the shape of the notch 20 (also forming retention means), in a position
of the inflation valve 2 in which the assembly head 4 is housed in the
lateral housing 12.

[0049]It is essential to note that such an installation of the inflation
valve 2 does not require a dead zone because the assembly head 4 may be
inserted directly, by presenting it inclined, into the lateral housing 12
designed to receive it. Accordingly, the dimensions and the weight of the
electronic modules 1 may be optimized.

[0050]For the purpose of installing the electronic unit on a rim 23, an
annular seal 28 (FIG. 3) is positioned about the intermediate section 7
of the body 3, so as to be compressed between the rim 23 and the insert
11 after said body is installed in a bore conventionally arranged in said
rim. This annular seal is contained (at least partially) in a metal cup
(not shown). Accordingly, during the tightening of the seal between the
rim and the insert, only metal parts are in contact with one another.

[0051]The inclination of the electronic module 1 is then adjusted
according to the angle α that defines the profile of the rim,
mainly in order to hold said electronic module in the recess 24 that
forms the bottom of the rim 23 and thereby to limit the stresses
sustained.

[0052]Finally, the electronic unit is locked by means of a (metal) nut 27
screwed onto the threaded end portion 7a of the intermediate section 7 of
the body 3.

[0053]Once this locking is achieved, the assembly head 4 is wedged and
locked against the insert 11 and the kinematic chain for transmitting the
forces therefore consists only of contacts between metal parts which
ensure an increased retention of the screwing torque.

[0054]In addition, the installation of the inflation valve 2 does not
require a dead zone because the assembly head 4 may be inserted directly
into the lateral housing 12 designed to receive it. Accordingly, the
dimensions and the weight of the electronic modules 1 may be optimized.

[0055]Dead zone" means a zone made in the module 10 solely to receive the
valve head, without being able to insert any electronics therein, as is
the case for example when the module is pierced right through in order to
house the inflation valve 2 therein. According to the invention, the
portion of the module containing the electronics is dimensioned solely to
receive these electronics. The zone 12 for receiving the valve head
(therefore for attachment between the valve and the module) is situated
outside the electronics compartment (laterally in the example shown).